The behaviour of a seismic wave is known to depend a great deal on the nature of the sites in which it propagates, particularly on the mechanical properties thereof.
It is known that deteriorations of civil engineering works are generally caused by the horizontal shears due to the surface wave, known as Rayleigh wave, of which the effects may be translated by caving-in or liquefaction of the ground.
Studies that have been able to be made on the effects of numerous earthquakes confirm that the mechanical properties of the surface layer of the earth, i.e. of the layer which extends down to about 30 m in depth, may considerably modify the effects associated with the surface propagation of the seismic wave, although the latter often originates at great depth.
It is an object of the present invention to provide means disposed around the civil engineering works, in order locally to modify the effect of site and to attenuate the surface wave in order to protect these works from the destructive effects of earthquakes.